How can I spawn a simple object (for now it is a cube) into the scene within a BP? I can’t find any docs about this and am greatly confused.
Use the Spawn Actor from Class node … you will need to get the location / transform where you want to spawn it.
This one might also help: https://wiki.unrealengine.com/Fun_with_Blueprints:_Spawning_Dynamic_Objects
I hope this helps.
You might also want to look into “Instanced Static Mesh” (without LOD) and “Hierarchical Instanced Static Mesh” (with LOD).
These are performant ways of placing the same mesh multiple times from blueprints. The downside is that if you do want to move them etc. they will all move together.
This is a simple blueprint that places a row of meshes each time the box collision is triggered: (Can also be a regular instanced static mesh)